Advice on building an AK with a virgin barrel.

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Looking for a bit of advice when it comes to AK building; specifically with regards to populating and pinning the barrel. Headspacing a virgin barrel is an easy enough job, but pinning it proved... for lack of a better word, disastrous. So one royally hooped trunnion and 90 dollars later we're ready to go back at it. This time with much less unbridled optimism.

My brother, friend, and I all decided to jump head first into AK building with absolutely no prior machining or gunsmiths behind us. Only thing we got going for us is hours of research. Which, clearly, were not enough. It's almost impressive how hard we screwed the original trunnion, and I very much intend to not do that again.

Seems like our first mistake using a standard 1/4" drill at 400RPM to drill the barrel (we were going to finish the hole with a reamer). The bit almost certainly walked right off course when we pressed down on it. Coupled with the low spindle speed, I think it spelled disaster. The assembly was put in a vice, aligned best to our little ability, and clamped to the drill press's table. I'm beginning to suspect that clamping it to the table was a mistake too. I also suspect we might not have aligned it perfectly. Finally we drilled it all the way through from one side. Also a bad idea.

So basically we did everything wrong. Wrong bit. Wrong speed. Bad alignment. Bad fixture. List goes on.

I've got an 1/4" 4 flute end mill on the way, and some aluminium tape to keep the flutes from cutting on the edges. Advice on the RPM would be nice, though. Hopefully that solves the walking issues. I've heard flipping the assembly over to meet in the middle is a good idea too, so we'll try that.

About aligning the piece, and keeping it aligned. How do you do it? This has me especially worried on the other features on the barrel that we don't have a reamer for. They need to be dead-nuts on, or else it's hooped. Should I keep the assembly in a vice, but don't lock the vice to the table? Should I just hold the piece under the drill press by hand? This has me all sorts of worried.

Finally, should we hand ream the barrel pin, ream it with the drill press, or ream it with a hand drill?

I'll probably ask more questions, but thanks for your advice anyways.
 
Have not build a AK but do some machining. First you want the part clamped solid so you have no movement. Any movement part or bit angle will through you off. I would use a drill press but make sure the table is 90 deg to the bit, most are not. This can be set with a square or a dial gauge. Then if you have some scrap, run a test piece to check it. Drill through and flip over and see if it aligns up and the bit passes through the hole. I do all my drilling on my mill, the best way to do it. Use a center drill to start the hole. Your biggest problem will be finding the top dead center so you go straight. Bits like to walk on curve surfaces, a short center drill removes the flex in the bit. Maybe add a flat where you want the drill bit to start, so it doesn't walk. Bit's must be sharp and correctly shaped so they will drill straight. If one side is off, they walk. Trying to drill from both sides is hard to get an alignment unless you have index spindle. I would not try it with a hand drill, way to hard to keep everything square. Depending on the use of the hole is weather I ream or not. If it's for rotating pins yes, if for locking (roll pin) no. If a solid pin is used to pin, depends on the pin, some are tapered, some have 1 end slightly larger. It does not hurt to ream. If doing so I like to under drill the hole by a few 1/000's.
 
The barrel steel may be harder than the trunnion or vice versa. That will contribute to the problem. When drilling holes (for flash hiders) to intersect the top radius of a barrel I used a short ball end mill. Stubby to reduce/eliminate flex and ball end because they cut better on a sloping/curved surface. I never had any problems when doing those back at the beginning of the 94 AW ban.
Not that I or anyone else here does not want to help, but I suggest that you find a forum that specializes in AK builds (there are several) as you will most likely get a better informed reply from those who do it regularly.
 
The barrel steel may be harder than the trunnion or vice versa. That will contribute to the problem. When drilling holes (for flash hiders) to intersect the top radius of a barrel I used a short ball end mill. Stubby to reduce/eliminate flex and ball end because they cut better on a sloping/curved surface. I never had any problems when doing those back at the beginning of the 94 AW ban.
Not that I or anyone else here does not want to help, but I suggest that you find a forum that specializes in AK builds (there are several) as you will most likely get a better informed reply from those who do it regularly.
I would go to AKfiles, but they're a PITA to join... or maybe I'm just too lazy. Dunno about any other AK specific forums worth their salt, though.
 
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The school of hard knocks teaches some very valuable lessons. Thanks for sharing. You are way farther along than I would be. Please continue to share you experiences. I found you post interesting and then some. My problem is I don't have much to add.
 
I've got an 1/4" 4 flute end mill on the way, and some aluminium tape to keep the flutes from cutting on the edges.

The tape won't prevent side cutting, but it will cause the flutes to clog with chips & mangled tape.

You're gonna have a really hard time doing what you're trying to do without a mill (or a substantial fixture). To get it done on a drill press, your best bet would be to use the dreaded Dremel tool to create a flat surface where the end mill will initially make contact and start cutting. Hopefully you bought a carbide cutter so you can keep your RPMs higher and tool pressure lower. Set things up as rigidly as you can and just take your time, being very liberal with cutting lubricants.
 
You need a milling machine to do the barrel pin hole. I built 2 AKs when the kits came with original barrels, not brave enough to do another one when BATF banned the barrel while I don't have a mill, need a heavy duty one.
 
For someone with little experience, I recommend a parts kit like this one, https://www.classicfirearms.com/amd65partialbuildproject762x39/
The main thing that it lacks is a receiver which can be purchased or made from a flat and template which is easier than what you are trying to do. From what I remember there are several other sources for a similar parts kit and as usual, YMMV.

A partial description,
"Kit Includes:New ESS 4140 Chrome Moly (non-chrome lined ) 1 in 10 twist, 16.5” barrel, pressed into the front trunnion and properly headspaced. Checked with Go/No-Go Gauges and live round. (Disclaimer for legal reasons - Headspace must be rechecked by a competent gunsmith after final assembly).

Original Bolt, Carrier and Piston will actually come complete and seated into upper assembly"
 
For someone with little experience, I recommend a parts kit like this one, https://www.classicfirearms.com/amd65partialbuildproject762x39/
The main thing that it lacks is a receiver which can be purchased or made from a flat and template which is easier than what you are trying to do. From what I remember there are several other sources for a similar parts kit and as usual, YMMV.

A partial description,
"Kit Includes:New ESS 4140 Chrome Moly (non-chrome lined ) 1 in 10 twist, 16.5” barrel, pressed into the front trunnion and properly headspaced. Checked with Go/No-Go Gauges and live round. (Disclaimer for legal reasons - Headspace must be rechecked by a competent gunsmith after final assembly).

Original Bolt, Carrier and Piston will actually come complete and seated into upper assembly"

I ain't buyin' a thing from sweaty Ben, and I definitely ain't buyin' an AK from him.

Second, if I don't ever try and fail at something, I'm never gonna get good at it. Yeah building one of those kits would be easier, but all the builds me brother and I want to do aren't easy projects.
 
I ain't buyin' a thing from sweaty Ben, and I definitely ain't buyin' an AK from him.

Second, if I don't ever try and fail at something, I'm never gonna get good at it. Yeah building one of those kits would be easier, but all the builds me brother and I want to do aren't easy projects.

You can find that kit elsewhere if you look along with the headspaced barrel/bolt combo. Dealing with that issue is a major difficulty in constructing the AK for proper functioning and to do it right requires the right tools used correctly. An out of battery discharge can ruin one's day, a full auto can get you a prison sentence, and feeding problems etc. are likely if done incorrectly.

I would advise then that you look up and purchase the Shotgun News Gunsmithing book which ties together a bunch of articles that originally appeared in the Shotgun News including building AK's from more or less parts with steps and pictures. You have to have the right tools to do something or you won't be that happy with the results. In his articles, Steve Mathews did all sorts of projects such as re-welding a Bren gun receiver and making it function with a bunch of parts or building a semi-auto 9mm from barstock.

There are a considerable number of complications dealing with a semi-auto that you just do not have with a bolt action or single shot because it is actually harder for example to make a semi-auto than a full-auto. Making the later qualifies you for a prison cell even if you did not intend for it to happen. Possession of an unregistered machine gun is enough. Then there is feeding issues, out of battery firing, magazine retention, peening of working surfaces, and other such fun that takes place when you fire a fair number of rounds in fairly rapid succession.

Look, there are folks here on the THR that are expert machinists that could probably make things like a FAL receiver or a Browning 1919 from barstock, properly heat treat it, and even manufacture the small parts necessary to get it to function. When you admit that you have no machining experience or the proper tooling to do a job, you are unlikely to get much help from them because they probably do not want any responsibility for what might happen. The folks at AKFiles are pretty good unless you argue an AR is better at helping educate on building one if you wish. A lot of them have built AK's with some pretty crude tooling with decent results--while some folks here might have done that--they do not post regularly here. Since you do not have much machining experience, the other forum that might help would be the practical machinist website where a lot of those folks know their way around tools https://www.practicalmachinist.com/vb/gunsmithing/ .

Most of the regular THR posters in the Gunsmithing forum are either gunsmiths/machinists with the proper tooling and knowledge to do what they want or folks wanting to fix one or the other problems that they have with a particular firearm but I haven't seen most of the regular posters here want to make an AK from parts over the years nor FAL's, CETME's, and so on. There are a number of regular THR posters that have done so with AR's.

Long and short of it, good luck with your project and best wishes for a successful outcome.
 
I built a put together AK years ago using an Egyptian kit and Romanian takeoff barrel, and bubba tools. Mine wasnt very pretty, but was safe and functioned very well. You’ve received some good advice here from some very talented machinists, and some people who are trying to help you. Don’t be a dick and summarily dismiss them. You asked for help here, remember?

Headspace is THE single critical measurement on the whole build. Everything else can be worked with to some degree.

Once you have your trunnion installed and the barrel is clocked correctly everything you do should be focused on drilling and pinning the trunnion and barrel together. Make a jig to hold everything in place the way you want it to. It doesnt have to be fancy or inventive. Just needs to hold everything firm and square. Once you have every thing lined up, squared up, and clamped down, don’t screw with it. Don’t flip the thing over again, because you’ll never get your two attempts to meet in the middle. Skip that advice. Your end mill will do the job. Go slow and use plenty of cutting fluid. RPM’s? Have no idea so don’t ask.

When you have the trunnion pinned and done you can focus on the other bits on the barrel. But treat each bit as its own operation and be careful to not allow them to cant over and get crooked before you drill.

You’ll hear stories of people being able to bang one of these together in an afternoon. That ain’t you. They have tools, fixtures, and lots of build experience. You have hours of research and an end mill. Take your time. Try not to do too much all at once. If you find yourself in deep water just stop, back up and think about the problem. There’s likely a fix out there for it already.
 
I built a put together AK years ago using an Egyptian kit and Romanian takeoff barrel, and bubba tools. Mine wasnt very pretty, but was safe and functioned very well. You’ve received some good advice here from some very talented machinists, and some people who are trying to help you. Don’t be a dick and summarily dismiss them. You asked for help here, remember?

I'm thankful, don't get me wrong. But "buy a pre-barreled kit" isn't advice on how to not screw up your virgin barrel. Well, I suppose it is advice on how not to screw up... just not the kind I'm looking for.

Just needs to hold everything firm and square

Second to drilling a circular hole, herein lies my biggest concern. Historically the barrel pins were drilled willy nilly by Ivan on virgin trunnions and barrels. They didn't need to be square to the trunnion, and apparently they often aren't. I don't even think there's a flat surface to even go off of on the rest of the barrel assembly. There's got to be a good way to align these without just assuming the holes are parallel to the trunnion. Now I could solve this by just drilling oversized, but a lot of people don't need to. Which leads me to believe there's some ancient Navajo trick that either I'm too stupid to comprehend, or no one's told me... probably because they assumed I wasn't this stupid.

You’ll hear stories of people being able to bang one of these together in an afternoon. That ain’t you.

That much is true. Tried it once, killed a trunnion. RIP in peace.
 
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